Is there a way to override only the style of bpmn objects that will be rendered when drag and dropped into the canvas. I want to restore all the object specific business functionalities, but Im trying to render a more stylish SVG.

e.g. Consider the start event:

I want to have all business functionalities( context elements, connection rules, settings menu…) of it, but want to change the complete appearance (without affecting default functionalities).

Have you made yourself familiar with bpmn-js and how it works internally yet? If it’s only about the visual representation you can add a custom renderer that takes care of rendering the elements you want to change. We have an example of a custom renderer in the custom elements example project. Simply add this renderer as an additional module when creating a bpmn-js instance.